I'm getting around 4 shares a minute (mining at 100Mh/s but I don't mind that much because the number of shares is what actually matters, right?) and since LTC/USD is 2 and it pays 50 LTC for every block reward, it should pay 100USD for every 713 shares (diff as I type) so I should be getting like $100 every 3 hours (which is pretty good indication my math is wrong) and that's because diff is just so low!

When I do this math for BTC it works just right. Aren't the mechanisms supposed to be very similar?

If you're getting 100Mh/s on bitminter with ltc you wont get the same, if thats what you base all your calculations on since ltc uses scrypt which is memory hard
– EnthusiastJun 17 '13 at 6:07

Correct me if I am wrong but what matters is the number of shares accepted right? I may be getting 1000x more hashes on Bitcoin than on Litecoin but the number of shares/minute is pretty similar. I know that you need 2^32 hashes in average to find a share on BTC, do you have any idea of what that number is for LTC?
– ThiagoJun 18 '13 at 1:24

So just to clarify, you're doing 4 shares a minute on a litecoin pool? Which pool is it or at what difficulty are those shares? That would allow us to actually calculate your effective scrypt mining performance and your chances of finding a block (which is then shared with the pool and you get your shares worth).
– cdeckerJun 18 '13 at 18:42

Right now I"m actually doing 14 shares a minute on Pooled Bits. With difficulty now at around 746, I should be getting a block every 53 minutes. There's clearly something wrong because I couldn't and I'm not!
– ThiagoJun 22 '13 at 23:09

2 Answers
2

That refers to shares of a certain difficulty: diff 1 Litecoin shares or diff 65,536 shares according to some mining clients (notably CGMiner).

Each found share has its difficulty. If the share's difficulty is equal to or higher than the worker's difficulty, it gets submitted by the worker and accepted by the pool.

At 713 difficulty, it will take on average 713 * 65,536 = 46,727,168 diff 1 shares to find a block. Likewise, it would take 713 * 65,536 / D diff D shares.

Note that, if you submit a diff 256 share at 128 worker difficulty, you get paid for a diff 128 share. So, assuming your worker difficulty is constant (LTC pools tend to use variable difficulty), your expected payout would be numbers of shares * worker difficulty * 50 / difficulty LTC, where both worker difficulty and difficulty should use the same metric (just use the values the mining client reports).

Aren't the mechanisms supposed to be very similar?

For Bitcoin mining, a diff 1 share (lowest possible worker difficulty) is found for every 232 hashes that are calculated. Since Litecoin's scrypt algorithm is about 1000 times slower than SHA256, mining Litecoins would have a very high variance if the same metric of worker difficulty was being used.

how do you know it refers to diff 65536 shares, where did you get that number from?
– ThiagoJun 25 '13 at 17:15

cgminer shows a difficulty of 50.4M for me right now (which is way above LTC's network difficulty right now, differently from BTC mining, where they match) so that means I should be earning even more. I can't find the "pool difficulty" on my pool's website, I even sent them an e-mail about this now. Which pool are you using?
– ThiagoJun 26 '13 at 11:41

Oh I got you, I had misunderstood your first message. Where did you take this 65536 number from?
– ThiagoJun 26 '13 at 16:23

Well now I've found that there is such a thing as a "pool difficulty". PooledBits got back to me and now I've found where the difficulty for worker is, it was and cgminer reported it "setting pool difficulty to 6". Apparently, it keeps changing it all the time dynamically. I notice that each share I submit has a corresponding difficult and cgminer even reports what was the highest difficult share I submitted. So to get to my resulting earning, should I do number of shares * difficulty of every share * 50LTC / 65536 ?
– ThiagoJun 26 '13 at 18:19

oh wow, now that explained everything to me. Now I get why the share / hashrate math wasn't matching like they do on BTC: LTC pools use variable difficulty! Thanks so much, that was really valuable :) You can make the edit and include it in your main answer if you want to, I would do it myself but I'm new here and I don't know if it's alright for me to do that.
– ThiagoJun 26 '13 at 23:13

Correct me if I am wrong but what matters is the number of shares accepted right? I may be getting 1000x more hashes on Bitcoin than on Litecoin but the number of shares/minute is pretty similar. I know that you need 2^32 hashes in average to find a share on BTC, do you have any idea of what that number is for LTC?
– ThiagoJun 18 '13 at 0:27

@Tom: The number of shares is irrelevant. What matters is the number of shares multiplied by the share difficulty.
– David SchwartzJun 24 '13 at 18:19